1. Field of the Invention
The present invention relates to a piston for internal combustion engines with a piston head and a separate piston skirt joined together by the piston pin. Pistons with a separate head and skirt provide better guidance for the piston head. The piston head is provided with ring grooves and lands between the ring grooves. More particularly, it relates to such a piston where the second land is oval with the large diameter of the oval generally being aligned with the major diameter of the piston. Additionally, the fourth land is oval with the large diameter of the oval generally being aligned with the minor diameter of the piston. Alternatively, the second land can have the shape of two ovals rotated 90.degree. apart with the large diameter of one oval generally being aligned with the major diameter and the large diameter of the second oval generally being aligned with the minor diameter.
2. The Prior Art
Circular pistons which are known distort when heated and may cause excessive friction. The prior art, according to DE-A-38 38 217, discloses guiding a one-part piston with certain areas in the major and minor diameter direction. The means disclosed for guidance cannot be utilized with pistons with a separate head and skirt. Guidance of the cylinder at individual points is described in DE-A-34 32 369. This does not involve support areas in the major diameter direction, or minor diameter direction, however.